Role of perfusion medium in rewarming machine perfusion from hypo- to normothermia.

BACKGROUND: Gradual warming up of cold stored organ grafts using a controlled machine perfusion protocol facilitates restitution of cellular homeostasis and mitigates rewarming injury by adapted increase of temperature and metabolism. The aim of the present study was to compare intra- and extracellular type perfusion media for the use in machine perfusion-assisted rewarming from hypo- to normothermia. METHODS: Rat livers were retrieved 20 min after cardiac arrest. After 18 h of cold storage (CS) with or without additional 2 h of rewarming machine perfusion from 8°C up to 35°C with either diluted Steen solution or with Belzer MPS, liver functional parameters were evaluated by an established ex vivo reperfusion system. RESULTS: Rewarming machine perfusion with either solution significantly improved graft performance upon reperfusion in terms of increased bile production, less enzyme release, and reduced lipid peroxidation compared to CS alone. Cellular apoptosis (release of caspase-cleaved keratin 18) and release of tumor necrosis factor were only reduced significantly after machine perfusion with Belzer MPS. Histological evaluation did not disclose any major morphological damage in any of the groups. CONCLUSION: Within the limitation of our model, the use of Belzer MPS seems to be an at least adequate alternative to a normothermic medium like Steen solution for rewarming machine perfusion of cold liver grafts.

End-ischemic pharmacological cocktail treatment to mitigate rewarming/reperfusion injury.

Increasing shortage of donor organs leads to the acceptance of less than optimal grafts for transplantation, up to and including organs donated after circulatory standstill of the donor. Therefore, protective strategies and pharmacological interventions destined to reduce ischemia induced tissue injury are considered a worthwhile focus of research. The present study evaluates the potential of a multidrug pharmacological approach as single flush at the end of static preservation to protect the liver from reperfusion injury. Livers were retrieved from male Wistar rats 20 min after cardiac standstill. The organs were cold stored for 18 h, flushed with 20 ml of saline, kept at room temperature for 20 min, and reperfused at 37 °C with oxygenated Williams E solution. In half of the cases, the flush solution was supplemented with a cocktail containing metformin, bucladesine and cyclosporin A. Upon reperfusion, treated livers disclosed a massive mitigation of hepatic release of alanine aminotransferase and aspartate aminotransferase, along with a significant approximately 50 % reduction of radical mediated lipid peroxidation, caspase activation and release of TNF-alpha. Even after preceding cold preservation, a pharmacological cocktail given as single flush is capable to mitigate manifestations of reperfusion injury in the present model.

Intermittent hemodialysis as a rewarming strategy for severe hypothermia in patients without renal failure: a case report.

This case report highlights the effective use of intermittent hemodialysis (IHD) in warming a 71-year-old female patient with severe hypothermia who presented with a rectal temperature of 25 °C and signs of hemodynamic instability. The patient, found unconscious after prolonged exposure to cold exacerbated by alcohol consumption, initially showed some improvement in core temperature through active external rewarming methods. However, soon, her temperature plateaued at 27 °C. Patient was deemed unsuitable for extracorporeal membrane oxygenation (ECMO) or cardiopulmonary bypass (CPB) due to her age, and urgent IHD was initiated. This approach resulted in a stable increase in core temperature at approximately 2.0 °C/hr, along with normalization of lactic acidosis, creatinine phosphokinase, and correction of electrolyte imbalances, culminating in her full recovery and discharge after seven days in the hospital.After reviewing this case alongside similar ones from before, this case report highlights the efficacy and safety of IHD as an efficient, readily available, and less invasive method for rewarming moderate to severe hypothermic patients who are hemodynamically unstable patients but do not have cardiac arrest or renal dysfunction. IHD is especially useful when less invasive cooling devices (Artic Sun/ CoolGard) are not available or more invasive extracorporeal life support options (ECMO/ CPB) are either not indicated or unavailable. IHD can also help improve concurrent electrolyte imbalances and/or toxin buildup. The report further emphasizes the necessity of monitoring for potential complications, such as post-dialysis hypophosphatemia and rebound hyperkalemia, following successful rewarming.

Frostbite in the Pediatric Population: A Comprehensive Review and a Prospective Canadian Survey.

INTRODUCTION: Frostbite in the pediatric population, where skeletal maturity has not been achieved, can have important repercussions on subsequent growth. Yet, the optimal management of frostbite injuries in children remains vague. This review aims to summarize the current evidence for frostbite management in children and understand Canadian practice trends on this topic. METHODS: A review using Medline, Scopus, Web of Science, and gray literature was performed to identify relevant literature on the clinical manifestations, diagnostic methods, and treatment options in pediatric frostbite. An online survey was sent to plastic surgeons through the Canadian Society of Plastic Surgeons (CSPS) mailing list to further identify national practices and trends for pediatric frostbite management. RESULTS: A total of 109 articles were reviewed. No article provided a specific algorithm for pediatric frostbite, with existing recommendations suggesting the use of adult guidelines for treating children. Our survey yielded 9 responses and highlighted the rarity of pediatric frostbite cases, with no responder treating more than 10 cases per year. Most (55.6%) do not use a pediatric-specific treatment algorithm, whereas 30% apply adult guidelines. A conservative approach focusing on rewarming (55.6%), limb elevation (50%), and tetanus status verification (66.7%) was predominant. Imaging and surgical interventions seem to be reserved for severe cases. CONCLUSIONS: The current literature for pediatric frostbite management lacks specificity. Canadian practices vary, with a trend toward a conservative approach. The limited evidence and rarity of experience highlight the need for further research, ideally in a collaborative multicentric manner, to create a consensus for pediatric frostbite care.

The Outcome of Walking Cold Patients with Potential Mild Hypothermia to Safety-A Mountain Rescue Case Series.

INTRODUCTION: Some experts recommend that ambulant hypothermic patients should be rewarmed, fed, and not permitted to exercise for 30 min because of concerns that afterdrop can cause cardiac instability. We investigated the outcome of ambulant hypothermic patients in a case series from mountain rescue teams in Great Britain. METHODS: A questionnaire was used to collect information on a series of adult patients with a clinical diagnosis of mild hypothermia. All patients were alert on the AVPU scale and evacuated by walking from the mountain. The outcome measures were survival or a change in management because of medical deterioration during evacuation. RESULTS: A series of 108 eligible cases were reported over a 5-year period. When rescuers arrived on the scene, 98 (91%) patients were stationary, and 10 (9%) were still mobile. Thirty-eight (39%) of the stationary cases were walked immediately off the mountain without any on-scene delay. In the remaining 60 (61%) stationary cases, the decision was taken to delay evacuation to provide food, drinks, and additional clothing. In 3 cases, the use of heat packs indicated an intention to actively rewarm. In cases where the on-scene time was reported, 27 (79%) were known to be mobile again within 20 min. All patients survived, and no adverse medical events occurred in all 108 cases. CONCLUSIONS: In this study, no adverse events occurred because of immediate mobilization, suggesting that in these cases, there appears to be minimal risk of early activity.

Physiological Impact of Hypothermia: The Good, the Bad, and the Ugly.

Hypothermia is defined as a core body temperature of <35°C, and as body temperature is reduced the impact on physiological processes can be beneficial or detrimental. The beneficial effect of hypothermia enables circulation of cooled experimental animals to be interrupted for 1-2 h without creating harmful effects, while tolerance of circulation arrest in normothermia is between 4 and 5 min. This striking difference has attracted so many investigators, experimental as well as clinical, to this field, and this discovery was fundamental for introducing therapeutic hypothermia in modern clinical medicine in the 1950s. Together with the introduction of cardiopulmonary bypass, therapeutic hypothermia has been the cornerstone in the development of modern cardiac surgery. Therapeutic hypothermia also has an undisputed role as a protective agent in organ transplantation and as a therapeutic adjuvant for cerebral protection in neonatal encephalopathy. However, the introduction of therapeutic hypothermia for organ protection during neurosurgical procedures or as a scavenger after brain and spinal trauma has been less successful. In general, the best neuroprotection seems to be obtained by avoiding hyperthermia in injured patients. Accidental hypothermia occurs when endogenous temperature control mechanisms are incapable of maintaining core body temperature within physiologic limits and core temperature becomes dependent on ambient temperature. During hypothermia spontaneous circulation is considerably reduced and with deep and/or prolonged cooling, circulatory failure may occur, which may limit safe survival of the cooled patient. Challenges that limit safe rewarming of accidental hypothermia patients include cardiac arrhythmias, uncontrolled bleeding, and "rewarming shock."

Rewarming Young Children After Drowning-Associated Hypothermia and Out-of-Hospital Cardiac Arrest: Analysis Using the CAse REport Guideline.

OBJECTIVES: Extracorporeal membrane oxygenation (ECMO) is recommended in adults with drowning-associated hypothermia and out-of-hospital cardiac arrest (OHCA). Our experience of managing a drowned 2-year-old girl with hypothermia (23°C) and cardiac arrest (58 min) prompted this summary using the CAse REport (CARE) guideline to address the question of optimal rewarming procedure in such patients. DESIGN/PATIENTS: Following the CARE guideline, we identified 24 reports in the "PubMed database" describing children less than or equal to 6 years old with a temperature less than or equal to 28°C who had been rewarmed using conventional intensive care ± ECMO. Adding our patient, we were able to analyze a total of 57 cases. MAIN RESULTS: The two groups (ECMO vs non-ECMO) differed with respect to submersion time, pH and potassium but not age, temperature or duration of cardiac arrest. However, 44 of 44 in the ECMO group were pulseless on arrival versus eight of 13 in the non-ECMO group. Regarding survival, 12 of 13 children (92%) undergoing conventional rewarming survived compared with 18 of 44 children (41%) undergoing ECMO. Among survivors, 11 of 12 children (91%) in the conventional group and 14 of 18 (77%) in the ECMO group had favorable outcome. We failed to identify any correlation between "rewarming rate" and "outcome." CONCLUSIONS: In this summary analysis, we conclude that conventional therapy should be initiated for drowned children with OHCA. However, if this therapy does not result in return of spontaneous circulation, a discussion of withdrawal of intensive care might be prudent when core temperature has reached 34°C. We suggest further work is needed using an international registry.

[Reducing the Incidence of Postoperative Hypothermia in Patients Undergoing Robotic-Assisted Mitral Valve Surgery].

BACKGROUND & PROBLEMS: Post-operation hypothermia tends to induce complications. Sixty percent of robotic-assisted mitral valve surgery patients experienced hypothermia while admitted to our intensive care unit (ICU), resulting in prolonged ICU stays and 57% (eight) of those patients with hypothermia also experiencing cardiac arrhythmia. The causes of hypothermia in our ICU included low temperature in the operating room, delayed initiation of blanket coverage after surgery, and lack of postoperative thermal blankets, insufficient cardiopulmonary bypass rewarming time, cold ICU beds, lack of in-service training for hypothermia, and lack of procedure auditing. PURPOSE: This intervention was designed to reduce the incidence of hypothermia in ICU patients undergoing robotic-assisted mitral valve surgery upon ICU admission from 60% to 36% and the one-hour hypothermia rate from 43.3% to 26%. RESOLUTIONS: We implemented several measures including increasing the room temperature, pre-heating the ICU bed, achieving team consensus regarding prolonging the rewarming time after cardiopulmonary bypass, establishing a blanket warming area for postoperative patient use, and holding in-service training to enhance the awareness of the nurses were implemented. RESULTS: The incidence of hypothermia in ICU patients receiving robotic-assisted mitral valve surgery upon ICU admission decreased from 60% to 19.4%, while the one-hour hypothermia rate decreased from 43.3% to 19.4%. CONCLUSIONS: Using systemic interprofessional collaboration, combined thermal care can be achieved to significantly reduce the incidence of postoperative hypothermia in patients undergoing robotic-assisted mitral valve surgeries resulting in higher patient care quality and shorter ICU stays. We recommend applying this combined method to improve the quality of perioperative care for long-duration and major surgical procedures that involve large postoperative wounds and for patients who may require wider exposure during their operation.

Clinical use of controlled oxygenated rewarming of kidney grafts prior to transplantation by ex vivo machine perfusion. A pilot study.

BACKGROUND: Sudden restoration of normothermic conditions upon reperfusion of cold-stored grafts has been suggested to entail a massive energy demand not yet met by the cells that still suffer from hypothermic torpor. An adapted and gentle rise of graft temperature by ex-vivo machine perfusion has, therefore, been proposed. This should now be tested in the clinical setting. METHODS: In a first clinical series, six ECD-kidneys were subjected to controlled oxygenated rewarming (COR) during short term pre-implantation machine perfusion. Matched kidneys that were conventionally kept on ice served as controls. RESULTS: Early allograft function after transplantation was significantly improved by COR. On post-operative day 7, clearance of creatinine was more than twofold higher after COR and fractional excretion of sodium in the normal range, while significantly elevated in control kidneys. Good correlations were seen between ulterior graft function and real-time parameters obtained during pre-transplant machine perfusion (Lactate: r2  = .9; TIMP2: r2  = .74). Conventional denominators of graft viability like kidney donor risk index KDRI were far less predictive (r2  = .26). CONCLUSION: It is concluded that COR can be safely applied to renal grafts and appears to be a valuable tool to predict and improve early renal function after transplantation.

Successful recovery of severe hypothermia with minimally invasive central catheter.

BACKGROUND: Severe hypothermia can result in malignant arrhythmias or cardiac arrest and require invasive central rewarming modalities due to a core body temperature < 28 °C. Difficult rescue missions can make continuous CPR challenging, but the decrease in oxygen consumption at these low temperatures allows for successful recovery despite the delay. Although other active warming techniques, such as peritoneal lavage, intravascular warming catheter, and renal replacement therapy can be beneficial, the consensus statements recommend extracorporeal life support as the preferred rewarming method. CASE PRESENTATION: A 42-year-old female was found in a pond after presumed exposure for 30-40 min with an outside temperature of 17 °F (-8 °C) and was found to be in ventricular fibrillation. ACLS protocol was then initiated. At the hospital, she was intubated and sedated with continuous CPR during multimodal rewarming, including active internal via the ZOLL Icy catheter. One hour after rewarming, with core temperature above 29 °C, she was defibrillated and achieved ROSC. As she continued to warm, she made purposeful movement and was warmed and maintained at euthermia. She was initiated on antibiotics due to aspiration concerns and titrated off vasopressors with extubation on day 2 of hospitalization. She had mild complaints of extremity numbness and chest pain from compressions prior to discharge on hospitalization day 4. CONCLUSIONS: This case has a successful resuscitation of severe hypothermia associated with cardiac arrest. The patient was warmed at greater than 4 °C/h with a less invasive, quicker and potentially more available approach to warming. With equipment improvements, the ability to provide prolonged CPR while rewarming may suggest that transferring to an extracorporeal life support center is not necessary.

Resuscitation from severe accidental hypothermia by active core rewarming via an indwelling peritoneal dialysis catheter.

Accidental hypothermia is a life-threatening medical condition, which requires the appropriate rewarming strategy with careful monitoring. Active core rewarming is often necessary in the management of severe hypothermia. However, especially in the emergent clinical setting, immediate establishment of a reliable route for active core rewarming is difficult. Severe accidental hypothermia in patients dependent on peritoneal dialysis or combination of hemodialysis with peritoneal dialysis is extremely rare, and the ideal rewarming procedure for these patients is unclear. To our knowledge, this is the first case report illustrating the application of an indwelling peritoneal dialysis catheter to active core rewarming in the management of severe accidental hypothermia. A 64-year-old female with type 1 diabetes and end-stage renal disease (ESRD) on combination of hemodialysis with peritoneal dialysis was delivered to our hospital due to severe accidental hypothermia. On presentation, she was unresponsive and her core temperature was 22.8 °C. Since rewarming by an electric blanket and warmed saline infusion was ineffective, infusion of warmed peritoneal dialysis solution via an indwelling peritoneal dialysis catheter was performed in the emergency room. In the next few hours, her body temperature recovered to normal level, and she regained consciousness. During resuscitation, complications related to rewarming, such as arrhythmia or hypotension, were not observed. She was discharged without any sequelae. Indwelling peritoneal dialysis catheters, if available, could be utilized as the safe and reliable route for active core rewarming in ESRD patients.

Heated Humidified Breathing Circuit Rewarming in Hypothermic Patients Post-Cardiopulmonary Bypass-Pilot Study.

OBJECTIVES: Hypothermia on intensive care unit (ICU) admission after cardiac surgery and cardiopulmonary bypass is common. It contributes to postoperative complications including shivering, coagulopathy, increased blood loss and transfusion requirements, morbid cardiac events, metabolic acidosis, increased wound infections, and prolonged hospital length of stay. The current standard of care for rewarming ICU patients is forced air warming blankets. However, high-quality evidence on additional benefit rendered by other warming methods, such as heated humidified breathing circuits (HHBC), is lacking. Therefore, the authors conducted a pilot study to examine whether the addition of HHBC to standard forced air warming blankets in hypothermic patients (≤35°C) admitted to the ICU after cardiac surgery using cardiopulmonary bypass reduced time to normothermia. DESIGN: Prospective study conducted at a single large academic medical center. PARTICIPANTS: The study group was composed of 14 patients who were enrolled prospectively between April 1 and June 14, 2019. The study group was compared with a 2:1 matched retrospective control group. The matched group consisted of 28 patients from a 12-month period from July 1, 2018 June 30, 2019. INTERVENTIONS: Study patients received warming via forced air warming blankets and HHBC and were compared with patients in a control group who received only warming blankets. Time to normothermia, time to extubation, time to normal pH, blood loss, blood transfusions, and coagulation profile laboratory values were compared between the study and control groups. MEASUREMENTS AND MAIN RESULTS: The present study found no statistical difference in time to normothermia, for which the standard-of-care retrospective group achieved normothermia after a median (Q1-Q3) 4.8 (4.0-6.0) hours compared with 4.4 (3.5-5.5) hours in the prospective group receiving HHBC. All secondary outcomes, including time to extubation, time to normal pH, ICU blood product transfusion, chest tube output, and coagulation profile, were similar. CONCLUSIONS: The present pilot study detected a similar time to normothermia, extubation, and normal pH when HHBC were added to standard forced air warming blankets in hypothermic patients (≤35°C) admitted to the ICU after cardiac surgery using cardiopulmonary bypass. A future larger prospective study designed to detect smaller, but clinically meaningful, reductions in the time to key clinical events for patients treated with HHBC is feasible and warranted.

Successful Nonextracorporeal Life Support Resuscitation and Rewarming of a Patient with Hypothermia in Cardiac Arrest.

We report full recovery of a patient with hypothermia in cardiac arrest following continuous and prolonged cardiopulmonary resuscitation (CPR) and conventional, nonextracorporeal life support (non-ECLS) methods. A 57-y-old man presented with unwitnessed cardiac arrest and a core temperature of 23°C (73°F). The presenting cardiac rhythm was ventricular fibrillation. The team administered epinephrine and performed defibrillation and CPR. Because ECLS was unavailable at the facility, the medical team externally and internally rewarmed the patient using heated blankets, forced warmed air, thoracic lavage, and warmed IV fluids. The patient achieved return of spontaneous circulation after 4 h 56 min of continuous CPR and rewarming. The medical team admitted the patient to the intensive care unit. He achieved full neurologic recovery the following day. When ECLS is not available and transfer is not appropriate because of patient instability or hospital location, conventional rewarming methods and continuous, prolonged CPR can lead to successful outcomes in patients with hypothermia in cardiac arrest. This case demonstrates that CPR in patients with hypothermia-associated cardiac arrest can lead to full recovery.

Pediatric Environmental Cold Injuries.

Cold weather injuries are relevant concerns for children during winter sports and outdoor activities. To mitigate the risk of cold injury in this high-risk population, providers can educate parents on proper outdoor attire as well as the added risks of wind and water exposure. There are 2 types of environmental cold injuries: freezing injuries and nonfreezing injuries. Frostbite is a freezing injury from direct contact with cold air or surfaces. The extent of injury depends on the depth to which the freezing extends. Treatment involves rewarming the frozen tissue with warm water baths and considering analgesia. Hypothermia is a nonfreezing cold injury, and it can occur even when ambient temperatures are above freezing. When there is a decrease in the body's core temperature, hypothermia progresses from mild to severe symptoms. Treatment of hypothermia is threefold but is also dependent on the core body temperature, as colder core temperatures will require more aggressive warming techniques. Hypothermia treatment involves passive protection from further heat loss (ie, removing wet clothing), which helps the body to warm itself. Treatment also involves active external rewarming wherein a heat source, such as a heated blanket, is used to increase body temperature. Active internal rewarming is the delivery of heat inside the patient's body, such as warmed intravenous fluids.

Maintaining intravenous volume mitigates hypothermia-induced myocardial dysfunction and accumulation of intracellular Ca2.

NEW FINDINGS: What is the central question of this study? Detailed guidelines for volume replacement to counteract hypothermia-induced intravascular fluid loss are lacking. Evidence suggests colloids might have beneficial effects compared to crystalloids. Are central haemodynamic function and level of hypothermia-induced calcium overload, as a marker of cardiac injury, restored by fluid substitution during rewarming, and are colloids favourable to crystalloids? What is the main finding and its importance? Infusion with crystalloid or dextran during rewarming abolished post-hypothermic cardiac dysfunction, and partially mitigated myocardial calcium overload. The effects of volume replacement to support haemodynamic function are comparable to those using potent cardio-active drugs. These findings underline the importance of applying intravascular volume replacement to maintain euvolaemia during rewarming. ABSTRACT: Previous research exploring pathophysiological mechanisms underlying circulatory collapse after rewarming victims of severe accidental hypothermia has documented post-hypothermic cardiac dysfunction and hypothermia-induced elevation of intracellular Ca2+ concentration ([Ca2+ ]i ) in myocardial cells. The aim of the present study was to examine if maintaining euvolaemia during rewarming mitigates cardiac dysfunction and/or normalizes elevated myocardial [Ca2+ ]i . A total of 21 male Wistar rats (300 g) were surface cooled to 15°C, then maintained at 15°C for 4 h, and subsequently rewarmed to 37°C. The rats were randomly assigned to one of three groups: (1) non-intervention control (n = 7), (2) dextran treated (i.v. 12 ml/kg dextran 70; n = 7), or (3) crystalloid treated (24 ml/kg 0.9% i.v. saline; n = 7). Infusions occurred during the first 30 min of rewarming. Arterial blood pressure, stroke volume (SV), cardiac output (CO), contractility (dP/dtmax ) and blood gas changes were measured. Post-hypothermic changes in [Ca2+ ]i were measured using the method of radiolabelled Ca2+ (45 Ca2+ ). Untreated controls displayed post-hypothermic cardiac dysfunction with significantly reduced CO, SV and dP/dtmax . In contrast, rats receiving crystalloid or dextran treatment showed a return to pre-hypothermic control levels of CO and SV after rewarming, with the dextran group displaying significantly better amelioration of post-hypothermic cardiac dysfunction than the crystalloid group. Compared to the post-hypothermic increase in myocardial [Ca2+ ]i in non-treated controls, [Ca2+ ]i values with crystalloid and dextran did not increase to the same extent after rewarming. Volume replacement with crystalloid or dextran during rewarming abolishes post-hypothermic cardiac dysfunction, and partially mitigates the hypothermia-induced elevation of [Ca2+ ]i .

The efficiency of continuous renal replacement therapy for rewarming of patients in accidental hypothermia--An experimental study.

Severe accidental hypothermia carries high mortality and morbidity and is often treated with invasive extracorporeal methods. Continuous veno-venous hemodiafiltration (CVVHDF) is widely available in intensive care units. We sought to provide theoretical basis for CVVHDF use in rewarming of hypothermic patients. CVVHDF system was used in the laboratory setting. Heat balance and transferred heat units were evaluated for the system without using blood. We used 5L of crystalloid solution at the temperature of approximately 25°C, placed in a thermally insulated tank (representing the "central compartment" of a hypothermic patient). Time of warming the central compartment from 24.9 to 30.0°C was assessed with different flow combinations: "blood" (central compartment fluid) 50 or 100 or 150 mL/min, dialysate solution 100 or 1500 mL/h, and substitution fluid 0 or 500 mL/h. The total circulation time was 1535 minutes. There were no differences between heat gain values on the filter depending on blood flow (P = .53) or dialysate flow (P = .2). The mean heating time for "blood" flow rates 50, 100, and 150 mL/min was 113.7 minutes (95% CI, 104.9-122.6 minutes), 83.3 minutes (95% CI, 76.2-90.3 minutes), and 74.7 minutes (95% CI, 62.6-86.9 minutes), respectively (P < .01). The respective median rewarming rate for different "blood" flows was 3.6°C/h (IQR, 3.0-4.2°C/h), 4.8 (IQR, 4.2-5.4°C/h), and 5.4 (IQR, 4.8-6.0°C/h), respectively (P < .01). The dialysate flow did not affect the warming rate. Based on our experimental model, CVVHDF may be used for extracorporeal rewarming, with the rewarming rates increasing achieved with higher blood flow rates.

Use of the new preservation solution Custodiol-MP for ex vivo reconditioning of kidney grafts.

Organ shortage and the increasing use of extended criteria donor grafts for transplantation drives efforts for more efficient organ preservation strategies from simple cold storage toward dynamic organ reconditioning. The choice of a suitable preservation solution is of high relevance in different organ preservation or reconditioning situations. Custodiol-MP is a new machine perfusion solution giving the opportunity to add colloids according to organ requirements. The present study aimed to compare new Custodiol-MP with clinically established Belzer MPS solution. Porcine kidneys were ischemically predamaged and cold stored for 20 hours. Ex vivo machine reconditioning was performed either with Custodiol-MP (n = 6) or with Belzer MPS solution (n = 6) for 90 minutes with controlled oxygenated rewarming up to 20°C. Kidney function was evaluated using an established ex vivo reperfusion model. In this experimental setting, differences between both types of perfusion solutions could not be observed. Machine perfusion with Custodiol-MP resulted in higher creatinine clearance (7.4 ± 8.6 mL/min vs. 2.8 ± 2.5 mL/min) and less TNC perfusate levels (0.22 ± 0.25 ng/mL vs. 0.09 ± 0.08 ng/mL), although differences did not reach significance. For short-term kidney perfusion Custodiol-MP is safe and applicable. Particularly, the unique feature of flexible colloid supplementation makes the solution attractive in specific experimental and clinical settings.

Outcomes of patients suffering unwitnessed hypothermic cardiac arrest rewarmed with extracorporeal life support: A systematic review.

Prolonged cardiac arrest (CA) may lead to neurologic deficit in survivors. Good outcome is especially rare when CA was unwitnessed. However, accidental hypothermia is a very specific cause of CA. Our goal was to describe the outcomes of patients who suffered from unwitnessed hypothermic cardiac arrest (UHCA) supported with Extracorporeal Life Support (ECLS). We included consecutive patients' cohorts identified by systematic literature review concerning patients suffering from UHCA and rewarmed with ECLS. Patients were divided into four subgroups regarding the mechanism of cooling, namely: air exposure; immersion; submersion; and avalanche. A statistical analysis was performed in order to identify the clinical parameters associated with good outcome (survival and absence of neurologic impairment). A total of 221 patients were included into the study. The overall survival rate was 27%. Most of the survivors (83%), had no neurologic deficit. Asystole was the presenting CA rhythm in 48% survivors, of which 79% survived with good neurologic outcome. Variables associated with survival included the following: female gender (P < .001); low core temperature (P = .005); non-asphyxia-related mechanism of cooling (P < .001); pulseless electrical activity as an initial rhythm (P < .001); high blood pH (P < .001); low lactate levels (P = .003); low serum potassium concentration (P < .001); and short resuscitation duration (P = .004). Severely hypothermic patients with unwitnessed CA may survive with good neurologic outcome, including those presenting as asystole. The initial blood pH, potassium, and lactate concentration may help predict outcome in hypothermic CA.

Prognostic Value of P25/30 Cortical Somatosensory Evoked Potential Amplitude After Cardiac Arrest.

OBJECTIVES: The aim of this study was to evaluate the prognostic performance of the peak amplitude of P25/30 cortical somatosensory evoked potentials in predicting nonawakening in targeted temperature management-treated cardiac arrest patients. DESIGN: Prospective analysis. SETTING: Four academic tertiary care hospitals. PATIENTS: Eighty-seven cardiac arrest survivors after targeted temperature management. INTERVENTIONS: Analysis of the amplitude of P25/30. MEASUREMENTS AND MAIN RESULTS: In all participants, somatosensory evoked potentials were recorded after rewarming, and bilaterally absent pupillary and corneal reflexes were evaluated at 72 hours after the return of spontaneous circulation. We analyzed the amplitudes of the N20 and P25/30 peaks and the N20-P25/30 complex in cortical somatosensory evoked potentials. Upon hospital discharge, 87 patients were dichotomized into the awakening and nonawakening groups. The lowest amplitudes of N20, P25/30, and N20-P25/30 in the awakening patients were 0.17, 0.45, and 0.73 µV, respectively, and these thresholds showed a sensitivity of 70.5% (95% CI, 54.8-83.2%), 86.4% (95% CI, 72.7-94.8%), and 75.0% (95% CI, 59.7-86.8%), respectively, for nonawakening. The area under the curve of the P25/30 amplitude was significantly higher than that of the N20 amplitude (0.955 [95% CI, 0.912-0.998] vs 0.894 [95% CI, 0.819-0.969]; p = 0.036) and was comparable with that of the N20-P25/30 amplitude (0.931 [95% CI, 0.873-0.989]). Additionally, adding resuscitation variables or an absent brainstem reflex to the P25/30 amplitude showed a trend toward improving prognostic performance compared with the use of other somatosensory evoked potential amplitudes (area under the curve, 0.958; 95% CI, 0.917-0.999 and area under the curve, 0.974; 95% CI, 0.914-0.996, respectively). CONCLUSIONS: Our results provide evidence that the absence of the P25/30 peak and a reduction in the P25/30 amplitude may be considered prognostic indicators in these patients.

A Guideline-Based Policy to Decrease Intensive Care Unit Admission Rates for Accidental Hypothermia.

RATIONALE: Despite guidelines advising passive rewarming for mild accidental hypothermia (AH), patients are frequently admitted to intensive care unit (ICU) for active rewarming using a forced-air warming device. We implemented a new policy at our institution aimed at safely reducing ICU admissions for AH. We analyzed our practice pre- and post-policy intervention and compared our experiences with acute care hospitals in Connecticut. METHODS: A retrospective chart review was performed on 203 participants with AH identified by primary and secondary discharge codes. Our new policy recommended passive rewarming on the medical floors for mild hypothermia (>32°C) and ICU admission for moderate hypothermia (<32°C). Practices of other Connecticut hospitals were obtained by surveying ICU nurse managers and medical directors. RESULTS: Over a 3-year period, prior to rewarming policy change, 64% (n = 92) of patients with AH were admitted to ICU, with a mean ICU length of stay (LOS [SD]) of 2.75 (2.2) days. After the policy change, over a 3-year period, 15% (n = 9) were admitted to ICU (P < .001), with an ICU LOS of 2.11 (0.9) days (P = 0.005). In both groups with AH, altered mental status, infection, and acute alcohol intoxication were the most common diagnoses at presentation. Alcohol intoxication was more prevalent in the post-policy intervention group, pre 17% versus post 46% (P < .001). No complications such as dermal burns or cardiac arrhythmias were noted with forced-air warming device use during either time period. Among the 29 hospitals surveyed, 20 used active rewarming in ICU or intermediate care units and 9 cared for patients on telemetry units. Most hospitals used active external rewarming for core body temperature of <35°C; however, 37% of hospitals performed active rewarming at temperatures >35°Cor lacked a policy. CONCLUSIONS: Reserving forced-air warming devices for the treatment of moderate-to-severe hypothermia (<32°C) significantly reduced ICU admissions for AH.